An assembly of devices added/retrofitted to a manual wheelchair (occupant or attendant driven) to provide the occupant with an electrical-powered drive mechanism, including the energy source (batteries) to achieve this. The steering, control, and brake systems will typically be included. This retrofitted accessory may alter the wheel configuration of the wheelchair in order to provide the powered propulsion (e.g., from a conventional four-wheeled to a tricycle configuration or additional propulsion wheels at the rear of the wheelchair).